Oscillating Nernst-Ettingshausen effect in Bismuth across the quantum limit

In elemental Bismuth, 10$^5$ atoms share a single itinerant electron. Therefore, a moderate magnetic field can confine electrons to the lowest Landau level. We report on the first study of metallic thermoelectricity in this regime. The main thermoelectric response is off-diagonal with an oscillating component several times larger than the non-oscillating background. When the first Landau level attains the Fermi Energy, both the Nernst and the Ettingshausen coefficients sharply peak, and the latter attains a temperature-independent maximum. A qualitative agreement with a theory invoking current-carrying edge excitations is observed.Comment: Final published versio

From Dimensional Reduction of 4d Spin Foam Model to Adding Non-Gravitational Fields to 3d Spin Foam Model

A Kaluza-Klein like approach for a 4d spin foam model is considered. By applying this approach to a model based on group field theory in 4d (TOCY model), and using the Peter-Weyl expansion of the gravitational field, reconstruction of new non gravitational fields and interactions in the action are found. The perturbative expansion of the partition function produces graphs colored with su(2) algebraic data, from which one can reconstruct a 3d simplicial complex representing space-time and its geometry; (like in the Ponzano-Regge formulation of pure 3d quantum gravity), as well as the Feynman graph for typical matter fields. Thus a mechanism for generation of matter and construction of new dimensions are found from pure gravity.Comment: 11 pages, no figure, to be published in International Journal of Geometric Methods in Modern Physic

Maximally inhomogeneous G\"{o}del-Farnsworth-Kerr generalizations

It is pointed out that physically meaningful aligned Petrov type D perfect fluid space-times with constant zero-order Riemann invariants are either the homogeneous solutions found by G\"{o}del (isotropic case) and Farnsworth and Kerr (anisotropic case), or new inhomogeneous generalizations of these with non-constant rotation. The construction of the line element and the local geometric properties for the latter are presented.Comment: 4 pages, conference proceeding of Spanish Relativity Meeting (ERE 2009, Bilbao

Intersection of Place, Working Parents and Food Assistance: Implications for Preventing Child and Adolescent Obesity

Background/Purpose: The cumulative effects of the environment, educational system, and social injustices contribute to child health disparities. Collectively, these factors create barriers to national efforts aimed at reducing childhood obesity. Thus, behavioral, social, and cultural contributing factors were examined. Methods: Parents and guardians of Texas (n=714) children were interviewed by telephone using the National Survey of Children’s Health (NSCH). Weight status and variables of interest were analyzed using logistic regression. Results: Based on parental response, Hispanic children were more likely to be overweight/obese (p =0.002). Child recipients of food stamps had higher obesity rates (p- =0.011). Parents with less than a high school education had significantly more overweight/obese children (50% and 56% respectively, p <0.001). Children who did not have at least one parent employed were more often obese/overweight (p <0.001). Uninsured children (p =0.014), uninsured in past 12 months (p =0.032) and public insurance use (p < 0.001) were more likely to be obese/overweight. Conclusion: Ethnicity, low-income, education, unemployment and food stamp use are associated with increased risk for obesity. Intervention programs for low income families should be guided by social ecology and family system theories to facilitate changes in the home environment to support healthier lifestyles

Organocatalysis for versatile polymer degradation

The use of a simple, cheap and effective organocatalyst, tetramethylammonium methyl carbonate, has been exploited for the transesterification of a range of commercial polymer samples. PLA, PCL, PC and PET have been successfully broken down into useful products, with the repolymerisation of DMT to PET demonstrated, highlighting a truly circular economy approach

Stochastic parareal: an application of probabilistic methods to time-parallelisation

Parareal is a well-studied algorithm for numerically integrating systems of time-dependent differential equations by parallelising the temporal domain. Given approximate initial values at each temporal sub-interval, the algorithm locates a solution in a fixed number of iterations using a predictor-corrector, stopping once a tolerance is met. This iterative process combines solutions located by inexpensive (coarse resolution) and expensive (fine resolution) numerical integrators. In this paper, we introduce a stochastic parareal algorithm with the aim of accelerating the convergence of the deterministic parareal algorithm. Instead of providing the predictor-corrector with a deterministically located set of initial values, the stochastic algorithm samples initial values from dynamically varying probability distributions in each temporal sub-interval. All samples are then propagated by the numerical method in parallel. The initial values yielding the most continuous (smoothest) trajectory across consecutive sub-intervals are chosen as the new, more accurate, set of initial values. These values are fed into the predictor-corrector, converging in fewer iterations than the deterministic algorithm with a given probability. The performance of the stochastic algorithm, implemented using various probability distributions, is illustrated on systems of ordinary differential equations. When the number of sampled initial values is large enough, we show that stochastic parareal converges almost certainly in fewer iterations than the deterministic algorithm while maintaining solution accuracy. Additionally, it is shown that the expected value of the convergence rate decreases with increasing numbers of samples

Identifying Motivators and Barriers for Wellness Programs to Inform Recruitment and Retention of Diabetes Prevention Programs (DPPs)

Obesity and type 2 diabetes (T2DM) has increased greatly in incidence in the United States over the past decade. Diagnosis of T2DM is typically preceded by insulin resistance, which is typically indicated by increases in fasting blood sugar and called pre-diabetes. The Diabetes Prevention Program (DPP) is a group-based program focused on improving diet and maintaining consistent exercise towards a lower body weight. It has been found that minimum weight loss and 150 minutes of moderate exercise is more effective at preventing T2DM than medication-based treatment. Therefore, the DPP has potential in preventing T2DM however currently faces obstacles concerning recruitment and retention. Unfortunately, only 1-5% of individuals who would benefit from the program actually sign up. In order to address this, researchers obtained RDC funding and partnered with YMCA to determine barriers and motivators to the DPP. Individuals were invited to an on-campus, pilot DPP aimed towards employees in a single building. All employees received an invitation to give feedback in 1 of 3 focus groups: 1 with those who joined the program and 2 with employees who did not join. There were 4 individuals in the focus group for DPP participants and 18 total who attended the other focus groups (one group of 5, and one group of 13). The focus group for current participants was scheduled during the time of a normal weekly meeting, while the group for non-DPP participants was during lunchtime. Questions centered around individuals\u27 perceptions on wellness programs, barriers to participation, and recommendations. Thematic analysis was done on notes taken at each focus group. Motivators found in the focus group with DPP participants included family history of diabetes, weight loss, desire to take control of lifestyle, hearing success stories, and support from others. A challenge faced by individuals going through the program included unsupportive family members or home environment. Themes found among the non-DPP participant focus groups gave greater insight in the negatives and barriers to wellness programs. Themes emphasized included importance of convenience, variability, coworker support, and appealing to individual interests. Overlapping themes included convenience, coworker support, and the importance of steering away from the \u27diabetes\u27 or \u27prediabetic\u27 labels. This study has significant impact especially in Tennessee where the DPP has become a covered benefit under insurance. In order to ensure strong recruitment and retention of these programs across the state and nation, researching further and addressing the motivators and barriers identified is key. With the DPP having such great potential in reducing risk of diabetes and obesity, a strong, intentional recruitment plan is necessary

Laplace transformations of hydrodynamic type systems in Riemann invariants: periodic sequences

The conserved densities of hydrodynamic type system in Riemann invariants satisfy a system of linear second order partial differential equations. For linear systems of this type Darboux introduced Laplace transformations, generalising the classical transformations in the scalar case. It is demonstrated that Laplace transformations can be pulled back to the transformations of the corresponding hydrodynamic type systems. We discuss periodic Laplace sequences of with the emphasize on the simplest nontrivial case of period 2. For 3-component systems in Riemann invariants a complete discription of closed quadruples is proposed. They turn to be related to a special quadratic reduction of the (2+1)-dimensional 3-wave system which can be reduced to a triple of pairwize commuting Monge-Ampere equations. In terms of the Lame and rotation coefficients Laplace transformations have a natural interpretation as the symmetries of the Dirac operator, associated with the (2+1)-dimensional n-wave system. The 2-component Laplace transformations can be interpreted also as the symmetries of the (2+1)-dimensional integrable equations of Davey-Stewartson type. Laplace transformations of hydrodynamic type systems originate from a canonical geometric correspondence between systems of conservation laws and line congruences in projective space.Comment: 22 pages, Late

Displacements of Metallic Thermal Protection System Panels During Reentry

Bowing of metallic thermal protection systems for reentry of a previously proposed single-stage-to-orbit reusable launch vehicle was studied. The outer layer of current metallic thermal protection system concepts typically consists of a honeycomb panel made of a high temperature nickel alloy. During portions of reentry when the thermal protection system is exposed to rapidly varying heating rates, a significant temperature gradient develops across the honeycomb panel thickness, resulting in bowing of the honeycomb panel. The deformations of the honeycomb panel increase the roughness of the outer mold line of the vehicle, which could possibly result in premature boundary layer transition, resulting in significantly higher downstream heating rates. The aerothermal loads and parameters for three locations on the centerline of the windward side of this vehicle were calculated using an engineering code. The transient temperature distributions through a metallic thermal protection system were obtained using 1-D finite volume thermal analysis, and the resulting displacements of the thermal protection system were calculated. The maximum deflection of the thermal protection system throughout the reentry trajectory was 6.4 mm. The maximum ratio of deflection to boundary layer thickness was 0.032. Based on previously developed distributed roughness correlations, it was concluded that these defections will not result in tripping the hypersonic boundary layer